Multiple pole relay switch



AprilL 21, 1964 R. w. BRENNEMAN ETAL 3,130,283

MULTIPLE POLE RELAY SWITCH l 44a 42a 41g 43g HARRY J. LEBHERZIJR.

A TTORNE Y Ap/lll 21, 1964 R. w. BRENNEMAN ETAL 3,130,283

MULTIPLE POLE RELAY SWITCH Filed Jan. '7, 1960 3 Sheets-Sheet 2INVENTORS REXFORD W. BRENNEMAN HARRY J. LEBHERZ, JR.

ATTORNEY April 21, 1964 Filed Jan. 7, 1960 R. W. BRENNEMAN ETAL MULTIPLEPOLE RELAY SWITCH 3 Sheets-Sheet 3 INVENTRS REXFORD W. BRENNEMAN HARRYJ. LE'BHERZl JR.

ATTORNEY United States Patent Oiice 3,139,283 MULTIPLE POLE RELAY SWITCHRexford W. Brenneman, ,Woodsborm and Harry J.

Lebherz, Jr., Frederick, Md., assiguors to Union- Everedy Company, Inc.,Frederick, Md. yFiled Jan. 7, 196i), Ser. No. 1,070

Claims. (Cl. 20G-104) This invention relates generally to a multiplecontact electromagnetic relay switch having inertially balanced movingparts of which the Larmature rotates within the solenoid coil and theswitch contact actuator, connected by balanced coupling to both ends ofthe armature, rotates coaxially with the armature.

With increasing necessity for effective remote operation and automaticguidance of vehicular systems, the need for a compact, high performance,shock resistant relay switch has becomemost acute. For particularly inrocket vehicles, the nonfuel weight limitation is so critical that nofunctional redundancy can be afforded; every component is essential toproper functioning; every component must operate perfectly to avoidfailure and complete loss of the vehicle. Components mounted within sucha vehicle are expected to undergo severe motional disturbances.Accordingly, military performancek specifications require thatcomponents perform reliably during and afterkvery severe shock,vibration and acceleration.

It is an object of this invention to provide a relay switch ofcharacteristicsso superior that it not only meets the requirements ofsuch specifications, but surpasses them by a substantial margin.

A further object of the invention is to provide a relay switch which isboth statically and dynamically balanced so as to be insensitive toshock, vibration and acceleration.

Another object of the invention is to provide a light weight, simplejyetrugged mechanism to withstand severe shock without contact failure andwithout becoming disabled.

` It is another object of the invention to provide an exceptionallyrigid bobbin structure by integrally connecting magnetizable polemembers and bobbin ends to a nonmagnetizable center member so as topreclude its dimensional distortions resulting from motionaldisturbances in operation. y

y Another 'object of the invention is to provide a coil bobbin ofyrectangular cross-sectional shape so that Coil wires directly woundthereon conform to this shape and yare thus highly resistant torotational displacement on the bobbin. y f It is'another object of theinvention to obtain a fully balanced armature, centrally pivoted andarranged in the magnetic circuit so that the magnetic force is appliedequally to both ends, thereby minimizing reaction on the pivot andassociated friction. n

Still another object of the invention is the balancing of the switchingforce applied to the armature by coupling the contact actuatorequallyfrom both ends of the armature. i

Another object ofthe invention is to permit the same type of power unitto actuate a variety of yswitching means yincluding a single multiplecontact array disposed parallel to the armature at one end, or a doublearray using both ends, kor microswitch contacts acted on directly by thearmature. l i

Another object kof the invention is the attainment of a compactarrangement of driving solenoid and contactsr readily packaged in asealed container which may be lled with various desirable liquids orgases.

By way of brief description, the switch may be considered as composed oftwo major parts: (l) the power head which includes the bobbin, polepieces, armature and coil winding; and (2) the switch contact assemblywhich maytake any of several forms. The power head contains but a singlemoving part, the armature, which is of generally rectilinear form. Thearmature is pivoted about an axle passing ythrough its center ofgravityand parallel to the longer side of its rectangular cross section.f The axle is mounted in a rectangular, knon-magnetic tube of generallysquare cross section. The lateral clearance between the rectangularexternal dimensions of the armature and square internal dimensions ofthe tube is occupied on opposite corners of the tube by magnetic polepieces which externally continuepthe tube Walls, and internally intrudeabout halfway toward .the pivot. Integral ilange material on each polepiece serves both to terminate the bobbin for coil winding and rto carrythe magnetic circuit to interconnecting ferro-magnetic circuit plates.The circuit plates likewise serve a dual purposek as they also provide asuitable base upon which the switch contact assembly may be mounted. Useof a rectangular armature and matching pole pieces isk particularlyadvantageous in that it provides a large area for the airgap, therebyminimizing the reluctance of this critical link in the magnetic circuitand assisting the effectiveness of the power head as a whole. y

The contact assembly of one form of the invention iS connected to thearmature by a spider-like actuator. This actuator is pivoted about anaxle mounted ona base plate which is attached to and generally parallelto one of the circuit plates; it extends the axis of rotation of thearmature. Two fingers, extending perpendicular to the plane of theactuator from opposite radial extremities, mate with slots provided inopposite ends of the armature. A plurality of armsy extending generallyradially from the yactuator pivot each support a driving pin extendingparallel to the axis of the spider and away from the coil. These eachengage a yresilient arm supporting a movable electrical contact. Fixedcontacts and the base anchors for the resilient arms are supported on abase plate attached to and parallel to the circuit plates.' Externalelectrical connection to the switch and coil winding passes through thebase plate. The base plate complete with contacts, actuating spider andpivot isr assembled and adjusted i11- dependentof the power head.

Many advantages result from this arrangement. By

coupling they spider actuator to both ends of the armature, loadingtorqueV applied to the armature is completely balanced. The restoringforce for the armature yand spider is inherent in the spring-likecharacter of each 0f the movable contact arms and is likewise balancedwith respect to the axis of the spider. Symmetry of both armaturevandactuating spider with respect to their common axis of rotation providesa condition of both static and dynamic inertial balance for theserelements. The integrated unit is extremely rugged, yet so compact thatencapsulation in a 'sealed `container 'is readily accomplished.

In another embodimentthe invention provides an additional Contact headermounted on the opposite magnetic circuit plate of the coil. In stillanother form,

pairs of microswitch units are mounted at both ends of referencecharacters denote the same component through- Patented Apr. 21, 1964amazes 3 showing the armature in relation to the pole pieces of themagnetic circuit;

FIG. 3 shows a side view of the pole pieces and magnetic circuit platesas projected on plane 3 3 of FIG. l;

FIG. 4 is a top view along section 4 4 of FIG. l, showing the actuatingspider in relation to the contacts;

FIG. 5 shows an adaptation of a single power head to actuation of twocontact header assemblies;

FIG. 6 shows an adaptation of the power head to actuation of eightmicroswitch units;

FIG. 7 is a side view of the assembly shown in FIG. 6;

FIG. 8 is an end view of the assembly shown in FIG. 6; and

FIG. 9 shows an actuating spider as in FIG. 4 but of modifiedproportions and an alternate means for anchoring the movable contacts.

The power head or rotary solenoid, designated generally as referencecharacter A in FIG. 1, is basic to all species of the invention. Thesolenoid structure is unusual in that its coil surrounds a rotatablearmature 1 which is a part of the magnetic circuit. The bobbin 2 extendsthe magnetic circuit to the ends of the coil unit by means of polepieces 3a and 3b, respectively right and left hand counterparts, bestshown in FIGS. 2 and 3. The pole pieces are fixed relative to each otherby attachment to the coil bobbin center 4. The bobbin center section isa hollow, square sectioned, cylindrical element of a nonmagneticmaterial such as tubular brass. A centrally located hole permitsinsertion of axle pin 5 which serves as a pivot for the armature 1. Themetal adjacent these holes is dimpled inward to space the armature withsufficient clearance from top and bottom walls of the bobbin tube.Opposite ends of bobbin tube 4 may be broken at right angles to provideflanges 9a and 9b to assist in attachment of the ferro-magnetic polepieces 3a and 3b and bobbin ends 8a and 8b. Rectangular portions ofopposite corners of the bobbin center 4 are removed, as shown in FIG. 2,to allow further joining of the pole pieces along junctions 6a and 6band location of the pole faces within the core structure in properregistry with the armature, as shown in FIG. 2.

The pole piece and bobbin ends are shown as single pieces 3a and 3balthough they may be fabricated of two or more parts to facilitatemanufacture. The actual pole regions '7a and ilD are solidparallelopipeds in shape protruding normally from the flange portions 3aand 8b. Externally on the bobbin, the pole surfaces constitute acontinuation of the generally flat surface of the bobbin center tube 4to the flanges 9. Internally, they intrude to meet the side surface ofthe armature 1 when it is aligned with respect to the longitudinal axisof the bobbin, 0r in its actuated position.

The bobbin ends are generally square when viewed from the end of thecoil (FIG. 3) and are centrally slotted at It) to permit extension ofthe armature through the bobbin ends. On the inner surface the bobbinends 3 are recessed to receive the flanges 9 broken in the bobbin center4. The outer surface contains a groove 11 generally perpendicular to theplane of rotation of the armature 1 to permit linkage connecting thearmature with the switch assembly yet to be described. Corners of thebobbin ends are removed along a circumferential path as viewed from thetop (FIG. 2) to permit encasement in a circularly cylindrical can 12 ofminimum size. Upper and lower surfaces 13 and 14 of the bobbin ends areflat and parallel (FIG. 3) so as to be readily bridged by ferromagneticcircuit plates 15 and 16. The magnetic circuit plates may be attached byscrew members such as 17 shown in FIG. 3, although other suitable meansof fastening may be employed.

Before the side plates can be attached, the armature 1 must be installedin the bobbin assemblage 3 and 4 and the coil must be wound. Thearmature is shaped as a rectangular bar element. The rectangularcnosssection (FIG. 3) provides a desirably large airgap area against itswide side where it contacts the pole faces 7. The pivot pin 5 may bejournaled in the armature and fixed in the bobbin center or vice versa.It is preferably of a ferro-magnetic material, such as hard steel, tomaintain continuity of the magnetic circuit section area in this region.Slotted grooves 1Sau and 18b are provided paral lel to the long side ineither end of the armature for eventual coupling of driving linkage forthe switching head or heads.

Once the armature is installed, the coil winding 19 may be applied. Thesize of wire and number of turns may be selected to suit requirements ofcurrent or voltage sensitivity, and other factors known to those skilledin the art. Since the external section of the bobbin is square, theturns of wire will assume a correspondingly shaped prolile. Theproportions indicated in the drawings provide room for adequate ampereturns in the solenoid. Suitable insulating tape and washers (not shown)be-f tween the bobbin core and ends and the coil winding are' desirableto reduce the likelihood of grounding on the metallic bobbin.

The magnetic flux induced by direct or alternating electrical current inthe coil 19 may be seen to pass through the armature 1, one pole piece7a, and the bobbin end 8a, in parallel through circuit plates 15 and 16to the opposite bobbin end 8b, to the opposite pole piece 7b, and thenceback to armature 1. The armature is urged into contact with the polepieces by solenoid action, that is into a position minimizing thereluctance of the magnetic c1rcuit. It is rotated away from the polepieces upon cessation of the energizing current by a constantly appliedresilient restoring torque mechanically coupled to the armature endslots 1S from the switching head or heads, yet to be described. From theforegoing description 1t will be seen that the actuating torque from thesolenoid action is symmetrically applied with respect to axle 5, thusminimizing lateral thrust and associated friction on this pivot.

A single switch contact header, encompassed generally by referencecharacter B, is provided in one embodiment of the invention, illustratedin FIGS. l, 2 and 4. In the foregoing description of magnetic circuitplates 15 and 16, their function in completing the magnetic circuit wasnoted. Plate 15 also provides a suitable structure for attachment of thecontact assembly. Four generally radial arms 2t?, 21, 22 and 23 (FIG. 2)of this plate extend to the inner peripheral limits of can 12 to providea base for standoff legs 24, 25, 26 and 27, respectively (FIG. 3). Endportions of these legs are reduced in circumferential extent so as toprovide shoul* ders typied by 24S in FIG. 3 lying in a plane parallel tothe plane of rotation of the armature. A base plate 2S for the contactassembly is slotted along its periphery to receive the ends of legs 24,25, 26 and 27 soi that a rigid attachment to the power head A may beelected.

The base plate 28 is perforated to receive three lead-in terminals 29,3f) and 31 for each of six double pole single throw switches, designatedby added reference characters a through f. The six common terminals liein an inner circle centered on the switch axis while the twelvealternate terminals lie on a circle near the periphery of the base plate28. The switch sets are equally spaced in two groups of three, lying toeither side of a plane through the longitudinal axis of the coil. At anintermediate radial position on this plane, lead-in terminals V32. and33 are connected to the coil winding by way of leads 34 and 35.

-Each lead-in terminal is separated from base plate 28 by a cylindricalinsulating bushing typified by 36a, 37a and 3st corresponding to lead-interminals 29a, 3i]a and 31a and by 39 and 4tl= corresponding to coilenergizing lead-in terminals 32 and 33. The terminal leads anchored inthese bushings are of suiiicient stiffness to provide mechanical supportfor the contacts and switch arms. Taking set a as typical of all six (athrough f) fixed its supporting pin 31a.

In assembly of the pairsr of contacts, the liixed contact arms 432"L and44a may be Welded to their respective terminal pins so as to properlyposition the contacts with the needed clearance between contacts 41ELand 42a.

The spring 45a may also be attached by welding to pin 311iL but in anangular position which will bias the movable contact 46EL againstContact 42a with a positive pressure of a tixed value. i A pressure ofsome 3() grams per contact is permissible. The switch is then normallyclosed by resilient closure of contacts 46a and 42a; actuation isattended by closure of contacts 46JL and 41B.

Simultaneous actuation of the six single pole double throw switchassemblies is implemented by spider 49 (FIGS. l and 4)y which links thearcuate armature motion to the spring arms. The spider is pivoted abouta stud member 50, which is anchored at the center of base plate 2S andis shouldered so as to support the spider tor planar rotation in theregion above the contacts but below the ymagnetic circuit plate. kAresilient washer 50a f urges spider 49 into close contact with its seaton stud 50. kEight arms are provided on the spider, kkof which one pair,51a and 51D, longer than the rest, extend a radial distance equal to theradius of armature 1 so that vertical extensions 52a and 52h will engagethe slots 18a and 13b provided in the ends of armature 1. Angular motionof the'armature is thus directly coupled and transferred to the spider.Six shorter radial arms, such as 532e, are bent downward and terminatedwith beads typi'iedby 54l so as to make contact with spring arms 45aroughly midway between the fixed terminal 31a and movable contact 46a.

In operation, energization of relay coil 19 rotates armature 1 to thepoles 7. In a corresponding rotation of spider 49, bead 54a pushescontact 46a from its normally'closed terminal contact 42a to normallyopen contact 41a. Wheny coil k19 is deenergized, the resilient forceequally applied in a tangential direction to each of the six pusherbeads 54a, through 54f quickly returns the armature to its open position(as shown in FIG. 2). The balance of restoring torque on the spiderminimizes reaction on the stud pivot Sti, making lfor reduced frictionand operational on current to o current lag or hysteresis gap. Like thearmature, the radial symmetry of the spider provides inherent dynamicand static inertial balance, thus rendering this moving part insensitiveto acceleration and shook. The rotational torque available from therotary solenoid of this invention is so powerful that substantial springcontact bias can be used. The movable contacts thus obtain a highcharacteristic frequency, rendering them resistant to shock andvibration;

The torque available from armature `1 is so high that an additionalswitching header may be driven by it, thus providing a total of twelvesingle pole double throw switches. This embodiment, shown in FIG. 5, isessentially the lower half of the single head switch of FIG. lduplicated on the upper half. Ihe heads would be paired for oppositespider rotation; for example, the lower head forcounterclockwiseactuation (as shown in FIG. 3) would require thatr theupper half be actuated by a clockwise rotation. Accordingly, the movablecontact arms would be reversed and slight re-orientation of the baseplate would be required. A suitable encapsulating container 55 andmounting flange may be provided for the double headed switch, as shownin FIG. 7

5. The mounting flange may be varied to suit particular designrequirements without departing from the scope of the invention.

Versatility of the power head A is illustrated by still anotherembodiment (FIGS. 6, 7 and 8), in which microswitch elements areactuated by it. Thus, in the slotted ends 118 ofthe armature 1rectangular plates 57?* and 57b are inserted and secured. These extendthe lateral surface of the armature plate 57EL to engage actuating.buttons 59a and 6l)a or" microswitches 61a and 62al and plate 57b tocorresponding elements with suflix b. Energization of the head unitdrives the armature in the direction required -to actuate theseswitches. v removal of energization, restoring spring members 64a' and64b. rotate the armature in the reverse direction to actuate two pairsof alternate microswitch elements 67a and 68a through contact with theirrespective actuating buttons '65a and 66a on one end and correspondingelement with suthxb at the other end. Themicroswitches are attached tothe pole pieces by means ot mounting brackets 63a and 63h. Themicroswitch elements shown are commercially available types and are notin themselves the subject of the present invention.

An alternate structural form for the actuating spider and movablecontact assembly is shown in FIG. 9. In this embodiment each radial arm53 has been extended so as to make contact with spring arm 45 throughbead 54, closer to its coatnct 46 than shown in FIG. 4. This engagementin close proximity to the concentrated mass of contact 46 providesimproved vibrational characteristics of the movable contact assembly.Also modified in FIG. 9 is the means for attachment of spring arm 45 toterminal pin 31. To facilitate forming the spring arms 45, the iinalbend at the pin has been omitted and instead a clip member v69 isattached to expedite location of the spring armsy 45 with respect to theterminal pin 31 during assembly. A straight backing plate 70 replacesthe angle 47 of FIG. 4 and permits spot welding of the spring armtermination to pin 31 to the backing plate 70. K

Itwill be noted in FIG. l that ther top of can 12 is fitted'into closeContact with magnetic circuit plate 16. This arrangement increases therigidity of the encapsulated unit .as a whole. In addition when the can12 is fabricated of ferromagnetic material, as will ordinarily be thecase, the can in this region serves to augment the magnetic yflux pathprovided by circuit plate 16.y To permit this close contact the innerflange 71 of nipple 72 is recessed in a hole 73 which is provided incircuit plate 16. The nipple 72 will normally be pinched off and sealedafter the can has been filled with a suitable liquid or gas.

What we claim is: 1. A solenoid actuated switch comprising (l) asupporting structure defining a reference axis fixed with respectthereto,

(2) a hollow cylindrical coil supported by said struc- .ture so that itslongitudinal axis intersects said reference axis at right angles and itsextremities are disposed symmetrically with respect thereto,

(3) a ferromagnetic armature member pivotably mounted within said coilto permit arcuate rotation about said reference axis when driven bysolenoid action of said coil and protruding radially therethrough atboth ends,

(4) a switch plate supportedfby said structure having a plurality ofcontacts ixed therein arrayed in radial symmetry about said referenceaxis,

(5) a corresponding plurality of movable contacts resiliently supportedon elastic arms mounted on said switch plate so as to be urged intocontact with said iixed contacts,

(6) a connecting spider mounted for rotation about said reference axishaving extensions lying generally parallel to and symmetrically`disposed about said reference axis and external of said coil whichengage protruding ends of said armature, and

Upon

(7) a plurality of radial arms extending radially from said referenceaxis each engaging one of said elastic arms whereby solenoid inducedarcuate rotation of the spider disengages each of said movable contactsfrom said fixed contacts and upon coil de-energization resilienceinherent in said elastic arms resets said armature.

2. A switch as in claim 1 but including a plurality of alternativecontacts aflixed to said switch plate in opposing relationship to saidfixed contacts whereby solenoid induced arcuate rotation of thusconnected spider engages each of said movable contacts with saidalternative contacts.

3. A switch as in claim 1 including a second switch plate, a secondplurality of movable contacts, a second corresponding plurality ofmovable contacts, a second connecting spider all similar to those rstnamed but disposed about said reference axis on its opposite extensionrelative to the armature and coil.

4. A switch as in claim 3 but including a plurality of alternativecontacts afhxed to each switch plate in opposing relationship to saidfixed contacts whereby solenoid induced arcuate rotation of thusconnected spiders engages each of said movable contacts with saidalternative contacts.

5. A switch as in claim 1 in which said armature memher is of generallyrectangular cross-section of longer sides disposed parallel its axis ofrotation.

6. A switch as in claim 5 including a second switch plate, a secondplurality of movable contacts, a second corresponding plurality ofmovable contacts, a second connecting spider all similar to those firstnamed but disposed about said reference axis on its opposite extensionrelative to the armature and coil.

7. A solenoid actuated switch comprising (l) a supporting structuredefining a reference axis fixed with respect thereto,

(2) a hollow cylindrical coil supported by said structure so that itslongitudinal axis intersects `said reference axis at right angles andits extremities are disposed symmetrically with respect thereto,

(3) a ferromagnetic armature member of generally rectangularcross-section with its longer side disposed parallel to the referenceaxis, said armature member being pivotally mounted within the said coilto permit arcuate rotation about said reference axis when driven bysolenoid action of said coil and protruding radially therethrough atboth ends to define symmetrically disposed slots in its peripheralextremities parallel to its axis of rotation,

(4) a switch plate supported by said structure having a plurality ofcontacts fixed therein arrayed in radial symmetry about said referenceaxis,

(5) a corresponding plurality of movable contacts resiliently supportedon elastic arms mounted on said switch plate so as to be urged intocontact with said fixed contacts,

(6) a connecting spider mounted for rotation about said reference axishaving axial extensions engaging protruding ends of said armature, and

(7) a plurality of radial extensions each engaging one of said elasticarms whereby solenoid induced arcuate rotation of thus connected spiderdisengages each of said movable contacts from said fixed contacts andopen coil de-energization resilience inherent in said elastic armsresets said armature.

8. A switch as in claim 7 in which the axial extensions of saidconnecting spider are engaged within said slots defined in theperipheral extremities of said armature.

9. A switch as in claim 7 including a second switch plate, a secondplurality of movable contacts, a second corresponding plurality ofmovable contacts, a second connecting spider lall similar to those firstnamed but disposed about said reference axis on its opposite extensionrelative to the armature and coil.

l0. A switch as in claim 9 in which the axial extensions of each of thetwo connecting spiders are engaged within said slots defined in theperipheral extremities of said armature.

References Cited in the file of this patent UNITED STATES PATENTS2,436,354 Burke et al. Feb. 17, 1948 2,549,323 McMullen et al Apr. 17,1951 2,606,981 Kesselring et al. Aug. 12, 1952 2,767,279 Hall Oct. 16,1956 2,836,674 Krantz May 27, 1958 2,843,696 Sturrup July 15, 19582,856,483 Farmer Oct. 14, 1958 2,888,533 Koda et al May 26, 19592,916,584 Molyneux Dec. 8, 1959 2,946,876 Lockwood et al July 26, 19602,951,134 Lazich Aug. 30, 1960 2,959,648 Williams Nov. 8, 1960 2,975,252Juptner Mar. 14, 1961 3,012,110 Price Dec. 5, 1961 3,030,469 Lazich Apr.17, 1962

1. A SOLENOID ACTUATED SWITCH COMPRISING (1) A SUPPORTING STRUCTUREDEFINING A REFERENCE AXIS FIXED WITH RESPECT THERETO, (2) A HOLLOWCYLINDRICAL COIL SUPPORTED BY SAID STRUCTURE SO THAT ITS LONGITUDINALAXIS INTERSECTS SAID REFERENCE AXIS AT RIGHT ANGLES AND ITS EXTREMITIESARE DISPOSED SYMMETRICALLY WITH RESPECT THERETO, (3) A FERROMAGNETICARMATURE MEMBER PIVOTABLY MOUNTED WITHIN SAID COIL TO PERMIT ARCUATEROTATION ABOUT SAID REFERENCE AXIS WHEN DRIVEN BY SOLENOID ACTION OFSAID COIL AND PROTRUDING RADIALLY THERETHROUGH AT BOTH ENDS, (4) ASWITCH PLATE SUPPORTED BY SAID STRUCTURE HAVING A PLURALITY OF CONTACTSFIXED THEREIN ARRAYED IN RADIAL SYMMETRY ABOUT SAID REFERENCE AXIS, (5)A CORRESPONDING PLURALITY OF MOVABLE CONTACTS RESILIENTLY SUPPORTED ONELASTIC ARMS MOUNTED ON SAID SWITCH PLATE SO AS TO BE URGED INTO CONTACTWITH SAID FIXED CONTACTS, (6) A CONNECTING SPIDER MOUNTED FOR ROTATIONABOUT SAID REFERENCE AXIS HAVING EXTENSIONS LYING GENERALLY PARALLEL TOAND SYMMETRICALLY DISPOSED ABOUT SAID REFERENCE AXIS AND EXTERNAL OFSAID COIL WHICH ENGAGE PROTRUDING ENDS OF SAID ARMATURE, AND (7) APLURALITY OF RADIAL ARMS EXTENDING RADIALLY FROM SAID REFERENCE AXISEACH ENGAGING ONE OF SAID ELASTIC ARMS WHEREBY SOLENOID INDUCED ARCUATEROTATION OF THE SPIDER DISENGAGES EACH OF SAID MOVABLE CONTACTS FROMSAID FIXED CONTACTS AND UPON COIL DE-ENERGIZATION RESILIENCE INHERENT INSAID ELASTIC ARMS RESETS SAID ARMATURE.